Grinding machine



March 27, 1934; BRQWN 1,952,653

GRINDING MACHINE Filed April 7, 1927 2 Sheets-Sheet l March 27', 1934. l P. BROWN 1,952,653

GRINDING MACHINE Filed April 7, 1927 2 Sheets-Sheet 2 I. 4% r a. j|; f: A: i 16 "551' 6 :55" kid I f 30 i :5

32 I 5:532? I I I k L G4 I Patented Mar. 27, 1934 GRINDING MACHiNE Francis P. Brown, Providence, I., assignor to Brown and Sharpe Manufacturing Company, a corporation of Rhode Island Application April 7, 1927, Serial No. 181,704

4 Claims.

The invention relates to grinding machines and of the surfaces of the work and especially to insure the proper grinding of the edge portions of this surface, as for instance, where the grinding wheel is working to a shoulde'na dwell is provided at each end of the reciprocating movement of the grinding wheel spindle.

. Means also are provided for throwing the remore particularly to a mechanism for reciprocating the grinding Wheel spindle.

The object of the invention is to provide a simplified and improved mechanism for imparting an axial reciprocation to a grinding wheel which will operate smoothly and efficiently and without excessive wear of the parts.

With this object in View, the features of the invention consist in the devices, combinations lo and arrangement of parts hereinafter described and claimed, and together with the advantages to be obtained thereby, will be readily understood by those skilled in the art from the following description taken in connection with the accompanying drawings.

In the drawings, Fig. '1 is a sectional view of the grinding wheel spindle of a grinding machine and the mechanism for imparting a reciprocating movement thereto, only so much of the machine being illustrated as is necessary to show the connection of the present invention thereto; Fig. 2 is a side elevation of the grinding wheel spindle reciprocating mechanism with a portion of the casing broken away; and Fig. 3 is an end view of the mechanism illustrated in Figs. 1 and 2.

In carrying out the invention, a differential mechanism is provided for imparting a relatively slow reciprocating movement in an axial direc-'- tion to the rapidly rotating grinding wheel spindle. This differential mechanism comprises a sleeve loosely mounted on the spindle and driven from the spindle at a slightly slower speed by means-of intermediate gears. A cam follower surface is formed on one end of the sleeve and is -adapted to engage with a cooperating cam surface on an abutting shoulder rigid with the spindle so that a reciprocating movement is imparted to the spindle which is dependent upon the relative rotary movements of the spindle and the sleeve. Compression springs tend to force the spindle in a direction to hold the cooperating cam and follower surfaces at all times in engagement with each other. In order to resist 45 the pressure of the springs in each direction, end thrust bearings are provided which cooper ate with the springs to control the axial movement of the spindle, the arrangement of these springs and bearings being such as to take up any wear of the parts and prevent any possibility of back lash which might interfere with the smooth and efi'icient operation of the mechanism.

In order to secure a more uniform grinding ciprocating mechanism out of operation when 'ciprocating mechanism.

Referring more specifically to the drawings, the grindingwheel is indicated at 4 secured to the grinding wheel spindle 6 which is mounted to rotate in bearings in the machine frame {8. As illustrated by Fig. 1, one end of the spindle is mounted in a bearing formed by the bushing-10 fixed in the frame 8, Secured to the spindle :6 and forming an extension thereof is the shaft 12 which carries loosely mounted thereon a sleeve 14 forming 'a part of the mechanism for reciprocating the spindle. The sleeve 14 is driven at a slightlyslower speed from the spindle by means of intermediate gears which comprise the gear 16 secured to the shaft 12, the gear 1E8 on the sleeve 14, and the gears 20 and formed on a rotatable sleeve 24 on, the shaft 25 and meshing respectively with the gears 16 a'nd l8.

Cooperating cam and cam follower surfaces are formed on the abutting ends of the sleeve 14 and a shoulder 26 which forms an integral part of the gear 16 rigid with the spindle so that a comparatively slow reciprocating movement in an axial direction is imparted to the spindle from the sleeve 14, due to the differential movement of the spindle and the sleeve.

The cam surface indicated at 30 is formed on the shoulder 23 and is arranged to engage the cooperating cam fol= lower surface formed by the two antifrict'ion rolls 28 mounted on each side of the sleeve The cam 30 is designed so that both rolls 28 will always-be in contact therewith and thus secure an even distribution of the strain. Y

The reciprocating movement imparted to the spindle as above set forth causes the grinding wheel to be moved continuously with relation to the work and prevents scoring of the polished surface due to any imperfections or roughness of the grinding surface.

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struction the advantages arising from the reciprocating movement are further enhanced by providing a dwell at each end of the reciprocating movement of the spindle, which has the effect of still further diversifying the travel of the grinding wheel on the surface of the work, and also has the advantage of insuring the proper cleaning out of material on those portions ofthe work which are reached only at the ends of the reciprocating movement of the grinding wheel. In the present disclosure the required dwell is obtained by the formation of the cam to produce the result.

The spindle is forced in a direction to hold the cam and follower surfaces on the abutting portions of the sleeve is and the spindle 6 in contact by means of compression springs 32 which are inserted between a flange 34 formed on the spindle and a ring 36 which is mounted to turn with the spindle but through which the spindle can move axially. The ring 36 bears against the bushing 10 and forms an end thrust bearing for the spindle to take up the pressure of the springs 32 in one direction. A flange 38 is provided on the sleeve 14 and bears against a fixed bearing ring 40 to form an end thrust bearing whichacts during the operation of the mecha nism for reciprocating the spindle to take up the pressure of the springs in the opposite direction.

The mechanism for reciprocating the spindle may be thrown out of operation by means of an adjustable block 42 which is adapted to engage the end 44 of the extension 12 of the spindle 6 to force the spindle against the pressure of the springs in a direction to disengage the cam and follower surfaces on the abutting portions of the spindle and. the sleeve 14. While the reciprocating mechanism is out of operation the spindle is held rigidly against axial movement between the end thrust bearings formed by the annular ring 36 and the block 42.

It will be noted that in the construction above described for reciprocating the spindle, the springs are located between the end thrust bearings and act to keep the cam and follower surfaces in contact, or, when thereciprocating mechanism has been thrown out of operation, to hold the end of the spindle in contact with the end thrust bearing formed by the adjustable block 42. All possibility of back lash in the mechanism is prevented by the intervention of the compression springs and as the parts wear down the mechanism is automatically taken up thus preventing any looseness and consequent uncertainty in the operation of the machine.

A hand lever 46 secured to one end of a rock shaft 48 is provided for actuating theblock 42 to throw the reciprocating spindle mechanism into and out of operation. The shaft 48 passes through an aperture in the block 42 and is provided with a cam surface including the flattened portion 50, which is adapted to engage with the flat surface of a hardened plate 52 secured to the block. In the position of the parts illustrated in Fig. 1, the flat portion of the shaft 48 is opposite the plate 52, thus permitting the block 42 to be retracted out of engagement with the spindle 14. By rotating the hand lever 46 a rounded portion of the shaft 48 will be brought into contact with the plate 52 causing the block to engage with the spindle and throw the reciprocating mechanism out of operation. In order to limit the rotation of the shaft 48, a stop screw 54 is adapted to engage with a groove 56 formed in the periphery of the shaft 48.

One form of the invention having been describedand illustrated and the advantages to be obtained thereby pointed out, what is claimed is:

1. In a grinding machine, the combination with v a grinding wheel of a grinding wheel spindle, a

sleeve loosely mounted to turn on the spindle, intermediate gears for rotating the sleeve from the spindle at a different rate of speed, cooperating cam and follower surfaces formed on abutting portions of the spindle and sleeve, an end thrust bearing for the sleeve, an en thrust bearing for the spindle, spring means for holding the corresponding cam surfaces in contact inserted between the thrust bearings to impart a reciprocating movement to the spindle in an axial direction, and mechanism including an additional end thrust bearing for the spindle arranged when rendered operative to engage with and move the spindle against the pressure of said spring means to disengage said cam and follower surfaces.

2. In a grinding machine, the combination with a grinding wheel of a grinding wheel spindle, a sleeve loosely mounted to turn on the spindle, intermediate gears for rotating the sleeve from the spindle at a different rate of speed, cooperating cam and follower surfaces formed on abutting portions of the spindle and sleeve, spring means for holding the cam and follower surfaces of the spindle and sleeve yieldingly in contact to impart a reciprocating movement to the spindle in an axial direction, and mechanism including an end thrust bearing for the spindle arranged to move the spindle against the pressure of said spring means to disengage said surfaces.

3. In a grinding machine, the combination with cooperating cam and follower surfaces in contact a to impart a reciprocating movement to the spindle in an axial direction, and an adjustable block adapted to engage the end of the spindle to move it against the pressure of the spring and disengage the cam surfaces.

4!. In a grinding machine, the combination with 7 a grinding wheel of a grinding wheel spindle, a sleeve loosely mounted to turn on the spindle, intermediate gears for rotating the sleeve from the spindle at a different rate of speed, cooperating cam and follower surfaces formed on abutting portions of the spindle and sleeve, a ring mounted on the spindle, compression springs inserted between the ring and the spindle to hold the corresponding cam surfaces in contact to impart a reciproeating movement to the spindle in an axial direction, an end thrust bearing for the ring, and an adjustable block adapted to engage the end of the spindle and force it against the pressure of the spring plungers to disengage the cam surfaces. FRANCIS P. BROWN. 

